Generally, in the prior art, the catalyst is prepared in two steps:
(a) the carrier is prepared or bought on the market, PA1 (b) an activating phase is then deposited on the carrier. It contains generally (.alpha.) at least one metal mostly from group VIII of the periodic classification of elements, generally present in the catalyst as metal or for example as oxide or sulfide and (.beta.) optionally at least one so-called additional metal or (or promoter) from any group of the periodic classification of elements, generally present in the catalyst as oxide or sulfide for example. PA1 (1) admixture of a charge, a binding agent and at least a portion of the active phase, PA1 (2) shaping of the mixture, PA1 (3) drying and optionally roasting, PA1 (4) optional introduction of the remaining portion of active phase, followed with a drying and then an activation. PA1 (a) 0.05-2% of at least one precious metal selected from platinum, palladium, iridium, ruthenium, rhodium and osmium (preferably platinum, iridium, ruthenium and rhodium) or 0.1-30% of at least one metal selected from iron, cobalt and nickel. PA1 (b) Optionally 0.01-25% of at least one second metal selected for example, from titanium, rhenium, tin, germanium, indium, thallium, manganese or still copper, silver, gold, niobium, lanthanum, cerium, samarium and other metals of the rare-earth family, zirconium, thorium, hafnium, lead, gallium, vandium, uranium, chromium, molybdenum, tungsten, zinc, cadmium, bismuth, antimony, etc . . . and PA1 (c) still optionally, for certain reactions, 0.1-10% of halogen, for example, chlorine or fluorine. PA1 (.alpha.) either in the charge, PA1 (.beta.) or in the binding agent, PA1 (.gamma.) or both in the charge and the binding agent. PA1 (.alpha.) the one or more metals from group VIII family (e.g. hexachloroplatinic acid), PA1 (.beta.) the one or more metals other than those from group VIII (e.g. a chloride, bromide, fluoride, sulfate or acetate of the selected metal or still any other salt of the selected metal soluble in water or in hydrochloric acid or in any other suitable solvent (e.g chloroplatinate, acetylacetonate) and PA1 (.gamma.) optionally chlorine or fluorine. PA1 a metal from group VIII, by means of a solution containing the same, PA1 one or more metals from group VIII (when the catalyst comprises several metals) by means of a solution containing the same, and PA1 finally the one or more other additional metals. PA1 (a) in several steps, or PA1 (b) in a single step. PA1 (a) either by extrusion, PA1 (b) or by the so-called method of the bowl granulator (or revolving bowl or revolving granulator, etc . . . ), PA1 (c) or by the so-called oil-drop method (drop falling in oil). PA1 by the method of the "revolving bowl granulator", or PA1 by the "extrusion" method, or preferably PA1 by anyone of the 6 "oil-drop" methods.
According to the prior art, several metals may be used to incorporate the active phase of the catalyst into the carrier:
Generally, each metal individually or all the metals together may be incorporated to the carrier by means of a suitable method, consisting in a co-precipitation or cogelation with the porous carrier or in ionic exchange with the gelated carrier or also in an impregnation of the carrier, either before or after the drying and roasting of the latter.